The present invention relates to a mechanical time piece having a hairspring holder adjusting mechanism capable of adjusting a position of a hairspring holder.
According to a conventional mechanical time piece, as shown in FIG. 6 and FIG. 7, a movement (machine body) 1100 of a mechanical time piece is provided with a main plate 1102 constituting a base plate of the movement. A winding stem 1110 is rotatably integrated to a winding stem guide hole 1102a of the main plate 1102. A dial 1104 (shown in FIG. 7 by an imaginary line) is attached to the movement 1100.
Generally, in both sides of the main plate, a side thereof having the dial is referred to as xe2x80x9cback sidexe2x80x9d of the movement and a side thereof opposed to the side having the dial is referred to as xe2x80x9cfront sidexe2x80x9d of the movement. A train wheel (or wheel train) integrated to the xe2x80x9cfront sidexe2x80x9d of the movement is referred to as xe2x80x9cfront wheel trainxe2x80x9d and a train wheel integrated to the xe2x80x9cback sidexe2x80x9d of the movement is referred to as xe2x80x9cback train wheelxe2x80x9d (or xe2x80x9cback wheel trainxe2x80x9d).
The position in the axis line direction of the winding stem 1110 is determined by a switch apparatus including a setting lever 1190, a yoke 1192, a yoke spring 1194 and a setting lever jumper 1196. A winding pinion 1112 is provided rotatably at a guide shaft portion of the winding stem 1110. When the winding stem 1110 is rotated in the state in which the winding stem 1110 is disposed at a first winding stem position (0-stage) which is the position furthest inward along the stem axis, the winding pinion 1112 is rotated via rotation of a clutch wheel. A crown wheel 1114 is rotated by rotation of the winding pinion 1112. A ratchet wheel 1116 is rotated by rotation of the crown wheel 1114. By rotating the ratchet wheel 1116, a mainspring 1122 contained in a barrel 1120 is wound up. A center wheel and pinion 1124 is rotated by rotation of the barrel 1120. An escape wheel and pinion 1130 is rotated via rotation of a fourth wheel and pinion 1128, a third wheel and pinion 1126 and the center wheel and pinion 1124. The barrel 1120, the center wheel and pinion 1124, the third-wheel and pinion 1126 and the fourth wheel and pinion 1128 constitute a front wheel train.
An escapement and speed control apparatus for controlling rotation of the front wheel train includes a balance with hairspring 1140, the escape wheel and pinion 1130 and a pallet fork 1142. The balance with hairspring 1140 includes a balance stem 1140a, a balance wheel 1140b and a hairspring 1140c. Based on rotation of the center wheel and pinion 1124, a cannon pinion 1150 is simultaneously rotated. A minute hand 1152 attached to the cannon pinion 1150 displays xe2x80x9cminutexe2x80x9d. The cannon pinion 1150 is provided with a slip mechanism relative to the center pinion and wheel 1124. Based on rotation of the cannon pinion 1150, via rotation of a minute wheel (not illustrated), an hour wheel 1154 is rotated. An hour hand 1156 attached to the hour wheel 1154 displays xe2x80x9chourxe2x80x9d.
The barrel 1120 is supported rotatably by the main plate 1120 and a barrel bridge 1160. The center wheel and pinion 1124, and the third wheel and pinion 1126, the fourth wheel and pinion 1128 and the escape wheel and pinion 1130 are supported rotatably by the main plate 1102 and a train wheel bridge 1162. The pallet fork 1142 is supported rotatably by the main plate 1102 and a pallet bridge 1164. The balance with hairspring 1140 is supported rotatably by the main plate 1102 and a balance bridge 1166.
The hairspring 1140c is a leaf spring in a helical (spiral) shape having a plural turn number. The inner end portion of the hairspring 1140c is fixed to an inner hairspring holder 1140d fixed to the balance stem 1140a. A stud support 1170 is rotatably attached to the balance bridge 1166. The rotational center of the stud support 1170 is the same as the rotational center of the balance with hairspring 1140.
As shown in FIG. 6 through FIG. 9, a hairspring holder 1172 is fixedly screwed to the stud support 1170 by a hairspring holder screw 1174. The outer end portion of the hairspring 1140c is fixed to the hairspring holder 1172. In a state in which the hairspring holder screw 1174 is loosened, the hairspring holder 1172 can be moved in a direction in parallel with the axis line of the balance with hairspring 1140.
A regulator 1168 is attached rotatably to the balance bridge 1166. A hairspring bridge 1168a and a hairspring rod 1168b are attached to the regulator 1168. A portion of the hairspring 1140c proximate to the outer end portion is disposed between the hairspring bridge 1168a and the hairspring rod 1168b. 
However, according to the conventional mechanical time piece, the hairspring holder can be moved only in a direction in parallel with the axis line of the balance with hairspring. Therefore, in fabricating a highly accurate mechanical time piece, it has been difficult to effectively carry out an operation of aligning the rotational center of the balance with hairspring and the center of the hairspring (the so-called operation of xe2x80x9ccentering of rotation of hairspringxe2x80x9d). That is, according to the operation of centering of rotation of the hairspring, there is needed an operation of adjusting the original shape of the hairspring by using hairspring tweezers.
The operation of adjusting the original shape of the hairspring is a very difficult operation even in the case in which an operator having a highly skilled technique carries out the operation. Therefore, there poses a problem in which fabrication of a highly accurate mechanical time piece requires an operator having a highly skilled technique and a long period of time.
It is an object of the invention to provide a mechanical time piece having a hairspring holder adjusting mechanism constituted such that the position of a hairspring holder relative to a rotational center of a balance with hairspring can be adjusted simply and firmly.
It is another object of the invention to provide a highly accurate mechanical time piece capable of easily carrying out adjustment of the original shape of a hairspring and facilitating fabrication thereof.
According to the invention, there is provided a mechanical time piece characterized in that in a mechanical time piece having a mainspring constituting a power source of the mechanical time piece, a front wheel train rotated by the rotational force from rewinding the mainspring and an escapement and speed control apparatus for controlling rotation of the front wheel train in which the escapement and speed control apparatus is constituted to include a balance with hairspring alternately repeating right rotation and left rotation, an escape wheel and pinion rotated based on the rotation of the front wheel train and a pallet fork for controlling rotation of the escape wheel and pinion based on an operation of the balance with hairspring, the mechanical time piece comprising a stud holder provided rotatably to a central axis line of a balance with hairspring, a hairspring holder attached to the stud holder to be movable orthogonal to the central axis line of the balance with hairspring, and a hairspring an inner end portion of which is fixed to the balance with hairspring and an outer end portion of which is fixed to the hairspring holder in the mechanical time piece having the mainspring constituting the power source of the mechanical time piece, the front wheel train rotated by the rotational force of rewinding the mainspring and the escapement and speed control apparatus for controlling the rotation of the front wheel train in which the escapement and speed control apparatus is constituted to include the balance with hairspring alternately repeating right rotation and left rotation, the escape wheel and pinion rotated based on the rotation of the front wheel train and the pallet fork for controlling the rotation of the escape wheel and pinion based on the operation of the balance with hairspring.
According to the mechanical time piece of the invention, it is preferable that an eccentric pin is rotatably attached to the stud holder, the eccentric pin includes an eccentric hole and the hairspring holder is integrated to the eccentric hole.
Further, according to the mechanical time piece of the invention, it is preferable that the mechanical time piece further comprises a hairspring holder setscrew for fixing the hairspring holder to the stud holder, wherein the eccentric pin includes a lateral hole formed in a shape of a long hole which is elongated at the opening such that the length thereof orthogonal to the central axis line is long and the length thereof the same direction as the central axis line is short, and the front end of the hairspring holder setscrew penetrates the lateral hole of the eccentric pin and fixes the hairspring holder by pressing on it.
Further, according to the mechanical time piece of the invention, it is preferable that the hairspring holder is rotatably integrated to the eccentric pin.
By constituting the mechanical time piece in this way, adjustment of an original shape of the hairspring holder can easily be carried out.
Further, according to the mechanical time piece of the invention, the eccentric pin is rotatably attached to the stud holder and accordingly, fabrication of the mechanical timepiece and adjustment of the hairspring are facilitated.